diff --git a/src/matrix/Session.js b/src/matrix/Session.js
index 90db1b68..4d30516a 100644
--- a/src/matrix/Session.js
+++ b/src/matrix/Session.js
@@ -35,10 +35,11 @@ export class Session {
         this._user = new User(sessionInfo.userId);
         this._olm = olm;
         this._e2eeAccount = null;
+        const olmUtil = olm ? new olm.Utility() : null;
         this._deviceTracker = olm ? new DeviceTracker({
             storage,
             getSyncToken: () => this.syncToken,
-            olm,
+            olmUtil,
         }) : null;
     }
 
diff --git a/src/matrix/e2ee/DeviceTracker.js b/src/matrix/e2ee/DeviceTracker.js
index 5eaa23b7..b085be80 100644
--- a/src/matrix/e2ee/DeviceTracker.js
+++ b/src/matrix/e2ee/DeviceTracker.js
@@ -36,11 +36,11 @@ function deviceKeysAsDeviceIdentity(deviceSection) {
 }
 
 export class DeviceTracker {
-    constructor({storage, getSyncToken, olm}) {
+    constructor({storage, getSyncToken, olmUtil}) {
         this._storage = storage;
         this._getSyncToken = getSyncToken;
         this._identityChangedForRoom = null;
-        this._olmUtil = new olm.Utility();
+        this._olmUtil = olmUtil;
     }
 
     async writeDeviceChanges(deviceLists, txn) {